1. Field of the Invention
The present invention relates generally to a document scanner and in particular to a flatbed scanner operating with a digital image capture module comprising two-dimensional (2D) optical image photo-sensor and in particular with a digital camera or digital video camera. The present invention further relates to flatbed scanners and means and methods of supporting cameras, and particularly, although not exclusively, to a flatbed scanner housing for holding a digital camera to allow the digital camera to act as a document capture device in obtaining digital images suitable for downloading to a personal computer or other computer peripherals such as a printer. The present invention further relates to a flatbed scanner housing holding a digital camera to allow the digital camera to act as a document capture device in obtaining digital images of hard to scan bound documents such as the opposing pages of thick books without any distortion at the protruding binding edge. The flatbed scanner of the present invention has the advantage of high speed instantaneous image capture of documents, low operation and energy costs, and is ideal for image capture of hard to scan objects such as bound documents especially near the binding edge that are inaccessible for the conventional flatbed scanners image reading heard.
2. Prior Art Reference and Discussion
It is known in the prior art to employ scanning devices to digitally record an image, commonly being a paper-based document e.g. a letter or photograph. Such scanning devices can download the digitally recorded data to a computer or other image processor where the data can be displayed on a visual display unit. This process enables the user to download an image of a document to a computer where the document can be manipulated or amended to the user's satisfaction. Following this, the document may be e-mailed, used in an electronic fax transmission, kept for later viewing or simply printed. Flatbed scanners are an additional option to incorporate into a desktop computer at additional expense. Known flatbed scanners comprise a base unit having a scan area to support a document or object being scanned. The flatbed scanner has a size dependent on the size of document for which the scanner is intended to image. Thus the desk top “foot print” of the scanner can be relatively large. Conventional flatbed scanners have resolution of the order of 600 dpi, which provides relatively high quality images, and it is common with more expensive prior art scanners to have resolution higher than 600 dpi.
There are several types of scanners available: scanner apparatus of the drum type, sheet-fed scanner, hand held scanner, flatbed scanner, and photographed image scanner which is the subject of this invention. A document scanner is comprised of a light source projecting a scanning beam to a document to be scanned. The scanning beam is reflected by or transmitted through the document and then received by optic detection devices which convert the reflected beam into electrical signals for further processing. An optic detection device that is commonly employed in the document scanner is a charge coupling device (CCD) although other types such as a charge injection device (CID), optical complementary metal oxide semiconductor (CMOS) array, an optical bipolar junction transistor (BJT) array, a photogate array, or a photodiode array are also used.
Recently, there have appeared digital cameras which have enabled an individual user to take high quality pictures, stored as digital images which can be downloaded to the user's personal computer. This is also the case with digital video camera. In fact many digital video cameras can be used as a still frame camera as well as for recording moving images. The resolution of digital cameras is rapidly increasing already being sufficient to capture legible images of A4/US letter pages and text will soon be able to rival the resolution provided by a flat bed scanner. These document reading apparatus employ an image capture mechanism incorporating a two-dimensional image reading photo-sensor (referred to as a 2D photo-sensor type) instead of the conventional one-dimensional image reading photo-sensor (referred to as a 1D or line photo-sensor type). An apparatus of the 2D photo-sensor type has a small number of 2D photo-sensor pixels and thus in the past had difficulty in reading images at a resolution high enough to clearly reproduce a color image or to be able to optically recognize characters on a document. Consequently, for image capture of documents, these types of photo-sensors were usually incorporated in an assembly comprising either a moving scanner (image reading) head or with a plurality of moving mirrors to compensate for the low resolution by sequential image capture.
In an image forming device including an image reading device such as a scanner, dot signals for one scanning line are detected by a 1D optical image photo-sensor usually a CCD photo-sensor. The CCD photo-sensor is placed in a moving scanner (image reading) head to sequentially scan an image horizontally one dpi at a time which slows down image capture. Although with that method of scanning higher resolutions may be obtained with a conventional moving-head flatbed scanners that it was possible with 2D digital image capture modules such as digital camera and digital video cameras, when scanning at high resolution of 600 dpi the scanning process takes longer time as the scanner image reading head moves slower compared to a resolution of 300 dpi for example.
The resolution of the 2D optical image (CCD) photo-sensor has ever since been increasing and its price dropping making it very attractive for use for instantaneous image capture. For example, 17 mega pixel photo-sensors are now available commercially (Canon EOS 1Ds Mark II 17.2 mega pixel digital camera). This is equivalent to an A4 size image with 250 pixels/inch resolution in 8 bit/channel RGB color which is good for most color image applications. It is also equivalent to an A4 size image with 430 pixels/inch resolution in 8 bit/channel grayscale which is more than that required for optical character recognition of fine text (8 point font). It is also equivalent to an A4 size image with 1200 pixels/inch resolution in bitmap which is four times more than that required for optical character recognition of black and white fine text.
A conventional scanner, which is called “flatbed” scanner, usually comprises a scanning module, a drive belt, signal transmission belt, a gear module, and a driving device. The driving device drives the transmission belt. It also comprises a cold cathode fluorescent lamp (CCFL) as the light source. The CCFL provides high brightness for scanning operation. However, the conventional flatbed scanner has the following disadvantages:
(1) The CCFL of a conventional flatbed scanner is operated with high voltage leading to the following disadvantages: high cost for providing the high voltage to drive the CCFL, safety concerns for the high voltage that drives the CCFL and the additional expense for safety increases the overall costs of the flatbed scanner, in addition, the up-transformation of voltage induces noise to the scanning operation of the flatbed scanner and thus adversely affects the scanning result.
(2) The regular power consumption of the CCFL is around 2.5 W, which makes it impractical to use the power interface regularly devised in a laptop computer since the battery is drained very rapidly. As such conventional flatbed scanners are energy inefficient and cannot be operated with batteries. Thus, an additional power adaptor is required. This also increases the costs and limits mobility. The higher power consumption further makes conventional flatbed scanners environmentally unfriendly.
(3) Flatbed scanners require method and apparatus for securing the scanner carriage. The belt could snap, scanner (image reading) head movement could generate noise which affects the image quality, and drive motor could malfunction.
(4) Image scanning is done sequentially line-by-line one dpi at a time with the scanning (image reading) head moving slowly. This type of linear image capture mechanism slows down image capture especially when scanning at high resolution leading to significant time consumption with extra cost for energy and manpower.
(5) Larger scanning time is required for higher image resolutions resulting in even higher energy and manpower costs.
(6) Conventional flatbed scanners usually take extra time to warm-up which adds more to the scanning time.
(7) Conventional flatbed scanners cannot usually be operated in a standalone mode and must be interfaced with PC which limits its functionality and mobility. Furthermore, remote control operation is also unprecedented.
(8) Conventional flatbed scanners are limited in paper size requiring larger scanning head for larger paper format with the extra cost.
(9) The space required by the moving image reading head incorporated in the conventional flatbed scanner makes it difficult to provide enough scanning glass room making it rather hard to scan bound documents such as books internal edges for example especially near the binding edge.
(10) Professional quality flatbed scanners are heavy weight and difficult to move and transport which affects the functionality and portability of the scanner.
(11) Conventional flatbed scanners comprise complicated driving mechanism with moving parts, mechanical assembly, or reflection mirror systems that are subject to wear and break down; The moving belt could snap, scanner head movement could generate noise which affects the image quality, and drive motor could also malfunction which makes the scanner less durable. Furthermore, the associated driving mechanism and reflection mirror system increase operation cost.
(12) Conventional flatbed scanners use constant illumination source (such as florescent light) during the whole scanning process which could take up to 2 minutes for one image scan. This result in high energy consumption per scanned image in addition to the power required to drive the motor to move the scanning head. Moreover, the light source is subject to malfunction.
It is thus desired to have a flatbed scanner that overcomes the above problems.
Among the prior art literatures that describe technologies related to these document reading apparatuses are the U.S. patents discussed below the teachings of which are incorporated herein by reference.
U.S. Pat. No. 4,831,455 (1989) to Ishikawa et al. and U.S. Patent Application no. 20030231354 (2003) to Shinoda et el. disclose a picture reading apparatus which comprises an electronic camera which converts a picture to be read to an electric signal and a supporting member for supporting the camera movably. The patent does not disclose or claim use of the invention in a flatbed scanner arrangement or incorporating the camera therein to function for the purpose of capturing images like a flatbed scanner.
U.S. Pat. No. 5,920,342 (1999) to Umeda et al. discloses an image input apparatus for capturing images of multiple resolutions comprising transferring an image signal from an electronic camera head to a personal computer and a supporting member for supporting the camera movably. The patent does not disclose or claim use of the invention in a flatbed scanner arrangement or incorporating the camera therein to function for the purpose of capturing images like a flatbed scanner.
U.S. Pat. No. 6,540,415 (2003) to Slatter et al. discloses a stand that facilitates and supports the use of digital cameras including digital video cameras in performing an equivalent function to a scanner in recording digital images which may be downloaded to a computer. The stand incorporates means for automatically configuring the camera into a mode of operation for document image capture on placing said camera into said stand. The patent does not disclose or claim use or incorporating of the digital camera in a flatbed scanner arrangement. In addition the said method poses difficulties in positioning the document for scanning. The images to be captured are placed on a table facing up with might not always be appropriate for image capture. In a flatbed arrangement the documents are usually placed facing down and pressed down flat into intimate contact with the scanning window. This feature is lacking in that invention which affects the produced image quality. The method further discloses imaging and combining low resolution six-point-text (135 dots per inch each) to provide one legible (high resolution) image when downloaded to a computer which is a major disadvantage time-wise.
U.S. Pat. No. 6,304,313 (2001), U.S. Pat. No. 6,812,995 (2004) and U.S. Patent Application no. 20010046036 (2001) all to Honma disclose a document processing system comprising a digital camera which performs accurate document reading, wherein a document is divided into blocks and each block is sensed by a CCD. An OCR process is performed on the image data to convert the corrected image data to text data which is output for further use. The patent does not disclose or claim use of the invention in a flatbed scanner arrangement or incorporating the camera therein to function for the purpose of capturing images like a flatbed scanner Furthermore, dividing the document to be scanner into blocks and sensing each block individually requires a plurality of CCD photo-sensors which is a major disadvantage both in terms of time and cost.
U.S. Patent Application no. 20030194111 (2003) to Kano et al. discloses a document reading apparatus comprising a table on which a document is set and a mounted 2D CCD image photo-sensor for image capture. The patent does not disclose or claim use of the invention in a flatbed scanner arrangement or incorporating the camera therein to function for the purpose of capturing images like a flatbed scanner. The patent further discloses a document reading apparatus comprising a 1D CCD image photo-sensor comprising a motor which drives the photo-sensor in a sub-scan direction thus having the same disadvantages of the conventional flatbed scanner.
U.S. Pat. No. 4,941,125 (1990) to Boyne discloses using a digital camera to scan documents and generate a corresponding digital output signal. A data processor receives the digital output signal and generates corresponding index information. The video and index information are then stored on one or more optical disks for search and retrieval. The patent does not disclose or claim use of the invention in a flatbed scanner arrangement or incorporating the camera therein to function for the purpose of capturing images like a flatbed scanner.
U.S. Pat. No. 5,475,441 (1995) to Parulski et al. discloses an electronic camera with memory card interface to a computer. The patent does not disclose or claim use of the invention in a flatbed scanner arrangement or incorporating the camera therein to function for the purpose of capturing images like a flatbed scanner.
U.S. Pat. No. 5,477,264 (1995) to Sarbadhikari et al. discloses an electronic imaging system includes a digital electronic camera for capturing and storing images in a removable storage device, whereby the imaging system further comprises a player device such as a computer. The patent does not disclose or claim use of the invention in a flatbed scanner arrangement or incorporating the camera therein to function for the purpose of capturing images like a flatbed scanner.
U.S. Pat. No. 5,636,006 (1997) and U.S. Pat. No. 5,847,846 (1998) both to Wu disclose apparatus and method for scanning a bound document using a wedge shaped platen with a moving mirror and a stationary 2D CCD image photo-sensor or using a drive assembly to move the document while image capture is accomplished sequentially line-by-line through a stationary 1D CCD imaging device. None of these patents disclose using digital camera as a method of image capture in a flatbed scanning arrangement and further comprise moving parts which have the same disadvantages of the conventional flatbed scanner.
U.S. Pat. No. 6,862,074 (2005) to Tretiakoff et al. discloses a portable device for photographing of book pages comprising two collapsible transparent plates and a digital camera. The patent does not disclose or claim use of the invention as a flatbed scanner or incorporating the camera therein to function for the purpose of capturing images like a flatbed scanner.
U.S. Pat. No. 5,814,809 (1998) to Han discloses an optical scanning apparatus for retrieving digital electronic images representative of opaque and transmissive object. The apparatus is equipped with a scanning camera moving within the scanner housing in the same manner as a conventional flatbed scanner, thus the disadvantages of the conventional flatbed scanner still exist.
U.S. Patent Application no. 20030117670 (2003) to Brugger et al. discloses a document scanning system with tethered platen element providing sheet-fed and platen scanning functions. The platen scanner contains a single camera comprised of a CCD or CMOS array and a motor for moving the camera thus the disadvantages of the conventional flatbed scanner still exist. Furthermore, the patent does not disclose or claim use of the invention in a flatbed scanner arrangement or incorporating the camera therein to function for the purpose of capturing images like a flatbed scanner.
U.S. Patent Application no. 20040268096 (2004) to Master et al. provides a digital imaging apparatus comprising at least one of a plurality of optical photo-sensors, the plurality of optical photo-sensors comprising: a charge coupling device (CCD), a charge injection device (CID), an optical complementary metal oxide semiconductor (CMOS) array, an optical bipolar junction transistor (BJT) array, a photogate array, or a photodiode array. The patent does not disclose or claim use of the invention in a solid state flatbed scanner arrangement with nonmoving parts or incorporating a digital camera therein to function for the purpose of capturing images like a flatbed scanner.
U.S. Patent Application no. 20030122953 (2003) to Huang et al. discloses a layout of the optical path in an image capturing system and a method for forming the same. The layout comprises a CCD or CMOS image photo-sensor with plurality of mirrors with improved optical path. The patent does not disclose or claim use of the invention in a solid state flatbed scanner arrangement with nonmoving parts or incorporating a digital camera therein to function for the purpose of capturing images like a flatbed scanner. Furthermore, the invention comprises a plurality of mirrors in a complex arrangement and a small opening for the optical path of image capture suggesting the captured image will have to be moved in front of the opening for image capture, which has the same disadvantages of the conventional flatbed scanner.
U.S. Pat. No. 5,870,624 (1999) to Kikinis discloses a personal desktop system for scanning and printing comprising a stationary line (1D) or area (2D) CCD image sensing with a drive assembly for moving the scanned images while scanning. This patent does not disclose using digital camera as a method of image capture in the flatbed scanning arrangement and further comprises moving parts which have the same disadvantages of the conventional flatbed scanner.
U.S. Patent Application no. 20030095620 (2004) to Lin discloses a flatbed scanner including housing inside which an optic detection system including a 1D CCD is mounted. The invention comprises a plurality of reflective surfaces and devices for reflecting the scanned image and a linearly-moving top platform on which the document is positioned to move the scanned image for the purpose of scanning it. The patent does not disclose or claim incorporating a digital camera in a flatbed scanner to function for the purpose of capturing images like a flatbed scanner. The presence of many components like reflecting surfaces and devices degrades the captured image quality and adds to the total cost of the scanner. Furthermore, the scanner has moving parts requiring motor drive assembly adding more to the cost and has the disadvantages of the conventional flatbed scanner such as breakdowns and the long scanning time since the scanning process with 1D CCD image photo-sensor is done sequentially one line at a time.
U.S. Pat. No. 5,150,227 (1992) to Koshiyouji et al. discloses an apparatus capable of reading a character or graphics image on a document at a plurality or reading linear densities using a 1D CCD photo-sensor for converting the focused light beam into an electric image signal. The carriage device containing the CCD line photo-sensor is moved in an auxiliary scanning direction in a desirable shifting which is determined on the basis of the reading sensitivity of the CCD reading photo-sensor and which corresponds to the linear reading density. The carriage device is motor driven and uses 1D line photo-sensor thus the disadvantages of the conventional flatbed scanner still exist.
U.S. Pat. No. 5,917,413 (1999) to Chou et al. and U.S. Pat. No. 6,545,769 (2003) to Collard et al. disclose an image processing apparatus comprising scanning of originals and converting then into digitized electrical image information using 1D CCD reading photo-sensor. This system comprises a moving linear image scanning components and reflective mirrors thus the disadvantages of the conventional flatbed scanner still exist.
U.S. Pat. No. 5,907,413 (1999), U.S. Pat. No. 6,389,183 (2002) and U.S. Pat. No. 6,608,707 (2003) all to Han disclose a flatbed scanner of the type commonly used as a stand-alone computer peripheral in combination with a contact image photo-sensor module to control the beginning and end of the scanning and accomplish scanning in two directions thus saving the need for carriage return prior to the next scan. The image scanning head is motor driven thus the disadvantages of the conventional flatbed scanner still exist. Furthermore, the patents do not disclose using digital camera or 2D image photo-sensors module as a method of image capture in the flatbed scanning apparatus.
U.S. Patent Application no. 20030202095 (2003) to Schultz discloses an optical scanner and method for 3D scanning comprising three CCD image photo-sensors mounted on a linearly-moving carriage. The carriage moving arrangement is motor driven thus the disadvantages of the conventional flatbed scanner still exist.
U.S. Pat. No. 5,276,530 (1994) to Siegel and U.S. Pat. No. 5,917,616 (1999) to Chou et al. disclose a book copying system which utilizes a height detector associated with the scan mechanism to obtain the distance between the image plane and portions of the image spaced from the image plane. Optical image data derived from scanning the original is converted to a digitized electrical image information using 1D CCD reading photo-sensor. This system comprises a moving image scanning components and reflective mirrors thus the disadvantages of the conventional flatbed scanner still exist.
U.S. Pat. No. 5,619,302 (1997) to Wu discloses an apparatus and method for scanning a bound document using a wedge shaped platen. This apparatus comprises a conventional flatbed scanner with moving scanning head. Thus the disadvantages of the conventional flatbed scanner still exist. Furthermore, this patent does not disclose using digital camera or 2D photo-sensor as a method of image capture.
U.S. Pat. No. 3,635,557 (1972) to Alderton discloses a method of presenting an image of a page of a book, so that the image may be photographically copied and apparatus for carrying out the method. The method uses a non-digital regular photographic camera which can not be digitally input to a computer for further use.
U.S. Pat. No. 3,888,584 (1975) to Smith, U.S. Pat. No. 4,415,225 (1983) to Huber et al., U.S. Pat. No. 4,585,334 (1986) to Malyon, U.S. Pat. No. 4,633,080 (1986) to Wilman et al., U.S. Pat. No. 5,953,819 (1991) to Malyon et al., U.S. Pat. No. 5,072,252 (1991) to Howsemen, Jr., U.S. Pat. No. 5,359,207 (1994) to Turner, and U.S. Pat. No. 5,526,098 (1996) to Peck et al. disclose improved document copying or scanning methods with improved angle-shaped platen design or scanning assembly for copying or scanning bound documents such as books by various methods. None of these patents discloses method or apparatus similar to the method of the present invention. The present invention having the advantages of simple design, ease of use, faster image capture and the ability to scan both opposing pages of bound documents simultaneously.
U.S. Pat. No. 4,068,950 (1978) to Kito discloses improved document copying method with improved L-shaped platen design with a generally horizontal copying top portion and a generally vertical side portion for copying bound documents such as books. The disclosed method or apparatus is claimed to copy only one page of a bound document at a time using the horizontal (top) copying portion.
U.S. Pat. No. 5,712,718 (1998) to Chen and U.S. Pat. No. 5,751,461 (1998) to Chen et al. disclose a book-edge flatbed scanner capable of scanning a thick book without any distortion at the protruding binding edge. The binding edge of the book is placed at the corner of a scanning glass window and the frame supporting the glass window so that the book can lie snugly over the window. The scanning window area is extended to the edge of the frame supporting the scanning window. The optical system and the driving mechanism lie inside the boundary of the scanning window to increase the scanning range. The scanner comprises a moving head with a 1D CCD image photo-sensor, thus the disadvantages of the conventional flatbed scanner still exist.
U.S. Pat. No. 5,801,849 (1998) to Solveychik et al. and U.S. Patent Application no. 20040218231 (2004) to Sheng et al. disclose a compact scanner the optical system of which is configured to extend in a particular direction beyond the document viewing area for improved resolution of images from a bound document adjacent the binding. The scanner comprises moving head with 1D CCD image photo-sensor, thus the disadvantages of the conventional flatbed scanner still exist.
U.S. Pat. No. 5,777,660 (1998) to Ard discloses a V-shaped scanning assembly for capturing the image of the pages of bound documents. The scanner assembly comprises a 1D CCD image capturing means in a moving assembly thus the disadvantages of the conventional flatbed scanner still exist.
U.S. Pat. No. 6,459,510 (2002) to Brewer et al. discloses a digital input scanner suitable for copying bound documents comprising a 1D CCD image capturing means in a moving assembly, thus the disadvantages of the conventional flatbed scanner still exist.
Accordingly, it is an object of the present invention to provide a digital scanning arrangement which avoids the disadvantages of the prior art.